Problem: What do the following two equations represent? $2x-y = 2$ $2x+4y = -5$
Putting the first equation in $y = mx + b$ form gives: $2x-y = 2$ $-y = -2x+2$ $y = 2x - 2$ Putting the second equation in $y = mx + b$ form gives: $2x+4y = -5$ $4y = -2x-5$ $y = -\dfrac{1}{2}x - \dfrac{5}{4}$ The slopes are negative inverses of each other, so the lines are perpendicular.